Freshwater Algae. Identification and Use as Bioindicators. Edward G. Bellinger Environmental Science and Policy, Central European University, Hungary

Transcription

1 Freshwater Algae Identification and Use as Bioindicators Edward G. Bellinger Environmental Science and Policy, Central European University, Hungary and David C. Sigee Manchester University, UK A John Wiley & Sons, Ltd, Publication

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3 Freshwater Algae

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5 Freshwater Algae Identification and Use as Bioindicators Edward G. Bellinger Environmental Science and Policy, Central European University, Hungary and David C. Sigee Manchester University, UK A John Wiley & Sons, Ltd, Publication

6 This edition first published 2010, C 2010 by John Wiley & Sons, Ltd Wiley-Blackwell is an imprint of John Wiley & Sons, formed by the merger of Wiley s global Scientific, Technical and Medical business with Blackwell Publishing. Registered Office: John Wiley & Sons, Ltd, The Atrium, Southern Gate, Chichester, West Sussex, PO19 8SQ, UK Other Editorial Offices: 9600 Garsington Road, Oxford, OX4 2DQ, UK 111 River Street, Hoboken, NJ , USA For details of our global editorial offices, for customer services and for information about how to apply for permission to reuse the copyright material in this book please see our website at The right of the author to be identified as the author of this work has been asserted in accordance with the Copyright, Designs and Patents Act All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means, electronic, mechanical, photocopying, recording or otherwise, except as permitted by the UK Copyright, Designs and Patents Act 1988, without the prior permission of the publisher. Wiley also publishes its books in a variety of electronic formats. Some content that appears in print may not be available in electronic books. Designations used by companies to distinguish their products are often claimed as trademarks. All brand names and product names used in this book are trade names, service marks, trademarks or registered trademarks of their respective owners. The publisher is not associated with any product or vendor mentioned in this book. This publication is designed to provide accurate and authoritative information in regard to the subject matter covered. It is sold on the understanding that the publisher is not engaged in rendering professional services. If professional advice or other expert assistance is required, the services of a competent professional should be sought. Library of Congress Cataloguing-in-Publication Data Bellinger, E. G. Freshwater algae : identification and use as bioindicators / Edward G. Bellinger and David C. Sigee. p. cm. Includes bibliographical references and index. ISBN (cloth) 1. Freshwater algae. 2. Indicators (Biology). 3. Environmental monitoring. I. Sigee, D. C. II. Title. QK B dc A catalogue record for this book is available from the British Library. ISBN Set in 10/12pt Times by Aptara Inc., New Delhi, India Printed in Great Britain by Antony Rowe, Ltd. Chippenham, Wilts First impression 2010

7 Contents Preface Copyright Acknowledgements ix xi 1 Introduction to Freshwater Algae General introduction Algae an overview Algae as primary producers Freshwater environments Planktonic and benthic algae Size and shape Taxonomic variation the major groups of algae Microscopical appearance Biochemistry and cell structure Molecular characterization and identification Blue-green algae Cytology Morphological and taxonomic diversity Ecology Blue-green algae as bio-indicators Green algae Cytology Morphological diversity Ecology Green algae as bioindicators Euglenoids Cytology Morphological diversity Ecology Euglenoids as bioindicators Yellow-green algae Cytology Morphological diversity Ecology Yellow-green algae as bioindicators 24

8 vi CONTENTS 1.7 Dinoflagellates Cytology Morphological diversity Ecology Cryptomonads Cytology Comparison with euglenoid algae Biodiversity Ecology Cryptomonads as bioindicators Chrysophytes Cytology Morphological diversity Ecology Chrysophytes as bioindicators Diatoms Cytology Morphological diversity Ecology Diatoms as bioindicators Red algae Brown algae 40 2 Sampling, Biomass Estimation and Counts of Freshwater Algae 41 A. PLANKTONIC ALGAE Protocol for collection Standing water phytoplankton River phytoplankton Mode of collection Phytoplankton trawl net Volume samplers Integrated sampling Sediment traps Phytoplankton biomass Turbidity Dry weight and ash-free dry weight Pigment concentrations Flow cytometry: automated analysis of phytoplankton populations Microscope counts of species populations Sample preservation and processing Species counts Conversion of species counts to biovolumes Chemical cleaning of diatoms Diversity within single-species populations Molecular analysis Analytical microscopical techniques 77

9 CONTENTS vii B. NON-PLANKTONIC ALGAE Deep water benthic algae Benthic pelagic coupling Benthic algae and sediment stability Invertebrate grazing of benthic algae Shallow water communities Substrate Algal communities Algal biofilms Mucilaginous biofilms Biomass Taxonomic composition Matrix structure Periphyton algal mats Inorganic substratum Plant surfaces 95 3 Algae as Bioindicators Bioindicators and water quality Biomarkers and bioindicators Characteristics of bioindicators Biological monitoring versus chemical measurements Monitoring water quality: objectives Lakes Contemporary planktonic and attached algae as bioindicators Fossil algae as bioindicators: lake sediment analysis Water quality parameters: inorganic and organic nutrients, acidity and heavy metals Wetlands Rivers The periphyton community River diatoms Evaluation of the diatom community Human impacts and diatom indices Calculation of diatom indices Practical applications of diatom indices Estuaries Ecosystem complexity Algae as estuarine bioindicators A Key to the More Frequently Occurring Freshwater Algae Introduction to the key Using the key Morphological groupings Key to the main genera and species 138

10 viii CONTENTS 4.3 List of algae included and their occurrence in the key Algal identification: bibliography 243 Glossary 245 References 255 Index 265

11 Preface Almost any freshwater or brackish water site will contain one or many species of algae. Although they are mainly microscopic and therefore not as visually apparent as larger aquatic organisms, such as higher plants or fish, algae play an equally important role in the ecology of these water bodies. Their presence can sometimes be noticed when they occur as dense populations, colouring the water and in some cases forming massive surface scums. Freshwater algae constitute a very diverse group of organisms. Their range of shapes and beauty when viewed through a microscope have delighted biologists for more than a hundred years. They have an enormous range of size from less than one micrometre to several centimetres (for the stoneworts) equalling the size span (10 4 ) for higher plants seen in a tropical rainforest Algal morphology is diverse, ranging from single cells to complex colonies and filaments. Some species are capable of active movement. The term algae embraces a number of phyla (e.g. Cyanophyta, Bacillariophyta and Chlorophyta) of chlorophyll-containing organisms with different growth forms and cytologies. Algae are important primary producers in both freshwater and marine systems. In many lakes and rivers they generate biomass which is the foundation of diverse food chains. Although algae have beneficial impacts on aquatic ecosystems they can also have adverse effects. When present in very large numbers they can produce blooms that, on decomposition, deoxygenate the water causing fish death and other ecological problems. Some algae produce toxins that are lethal to both aquatic and terrestrial organisms. It is important to be aware of these impacts and to monitor waters for the presence of these potentially harmful organisms. Algae can be used to flag up and assess a range of human and natural impacts in aquatic systems because of their often rapid response to changes in the environment. Examples include nutrient enrichment (eutrophication), industrial pollution and changes to the hydrological regime of the water body. Some groups of algae preserve well as fossils in geological deposits such as lake sediments, analysis of which gives us information on past environmental changes. This book comes at a time of increasing concern over the widespread effects of human activities on the general environment of this planet. Monitoring shifts in algal population gives us an insight into these changes. We need to be able to assess the health of aquatic systems such as lakes and rivers, since water is vital to both human and general ecosystem survival. Knowledge of algal population dynamics can help us develop effective management strategies for those systems. Included in this book are sections on the general features of the main freshwater algal groups with notes on their ecology, methods of sample collection and enumeration, using algae as indictors of environmental conditions and, finally, a key to the identification of the more frequently occurring genera. The authors have tried to combine descriptive material with original colour photographs and line drawings, where possible, to help the reader. We would also like to gratefully acknowledge the help and encouragement of colleagues and students, and particularly appreciate the direct contributions of postdoctoral workers and research students mentioned in the list of copyright acknowledgements. We would also like to thank our families for their understanding and patience during the preparation of this text. We hope that all those using the book will find it useful, and will enjoy the numerous colour photographs of these very beautiful organisms.

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13 Copyright Acknowledgements We are very grateful to the following individuals for allowing us to publish previously unpublished matter: Andrew Dean (Tables 2.3, 2.4), Matt Capstick (Figs , 4.42, 4.62, 4.64, 4.66, a, 4.73a) and Huda Qari (Fig. 2.8). We also thank the following copyright holders for giving us permission to use previously published material Academic Press, American Health Association, Cambridge University Press, Journal of Plankton Research, McGraw-Hill, Phycologia, Prentice Hall.

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15 1 Introduction to Freshwater Algae 1.1 General introduction Algae are widely present in freshwater environments, such as lakes and rivers, where they are typically present as micro-organisms visible only with the aid of a light microscope. Although relatively inconspicuous, they have a major importance in the freshwater environment, both in terms of fundamental ecology and in relation to human use of natural resources. This book considers the diversity of algae in freshwater environments and gives a general overview of the major groups of these organisms (Chapter 1), methods of collection and enumeration (Chapter 2) and keys to algal groups and major genera (Chapter 4). Algae are considered as indicators of environmental conditions (bioindicators) in terms of individual species (Chapter 1) and as communities (Chapter 3) Algae an overview The word algae originates from the Latin word for seaweed and is now applied to a broad assemblage of organisms that can be defined both in terms of morphology and general physiology. They are simple organisms, without differentiation into roots, stems and leaves and their sexual organs are not enclosed within protective coverings. In terms of physiology, they are fundamentally autotrophic (obtaining all their materials from inorganic sources) and photosynthetic generating complex carbon compounds from carbon dioxide and light energy. Some algae have become secondarily heterotrophic, taking up complex organic molecules by organotrophy or heterotrophy (Tuchman, 1996), but still retaining fundamental genetic affinities with their photosynthetic relatives (Pfandl et al., 2009). The term algae (singular alga) is not strictly a taxonomic term but is used as an inclusive label for a number of different phyla that fit the broad description noted above. These organisms include both prokaryotes (Section 1.3, cells lacking a membranebound nucleus) and eukaryotes (cells with a nucleus plus typical membrane-bound organelles). Humans have long made use of algal species, both living and dead. Fossil algal diatomite deposits, for example, in the form of light but strong rocks, have been used as building materials and filtration media in water purification and swimming pools. Some fossil algae, such as Botryococcus, can give rise to oil-rich deposits. Certain species of green algae are cultivated for the purpose of extracting key biochemicals for use in medicine and cosmetics. Even blue-green algae, often regarded as nuisance organisms, may have beneficial uses. This is particularly the case for Spirulina, which was harvested by the Aztecs of Mexico and is still used by the people around Lake Chad as a dietary supplement. Spirulina tablets may still be obtained in some health food shops. Blue-green algae are, however, are better known in the freshwater environment as nuisance organisms, forming dense blooms having adverse effects on human activities Freshwater Algae: Identification and Use as Bioindicators C 2010 John Wiley & Sons, Ltd Edward G. Bellinger and David C. Sigee